A simple, inexpensive method of aerial photography was used as a survey tool in an ecological study of the Avon-Heathcote Estuary, Christchurch, New Zealand. 35 mm colour and infrared colour and 5 × 5 inch (12.7 cm) black and white photographs were taken and used to map the vegetation and physical features of the Estuary. Reasonably accurate maps of the benthic algae, drainage pattern and shore line were produced. The pattern of exposure and the dispersal of sewage effluent and dye was also determined. The infrared film proved to be the most sensitive to low concentrations of algae and also highlighted the areas of active plants. It was less successful in areas where the algae were not exposed at low tide.